scholarly journals Regulation of the hyaluronan system in ovine endometrium by ovarian steroids

Reproduction ◽  
2013 ◽  
Vol 145 (5) ◽  
pp. 491-504 ◽  
Author(s):  
Kabir A Raheem ◽  
Waleed F Marei ◽  
Karen Mifsud ◽  
Muhammad Khalid ◽  
D Claire Wathes ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Protein Expression ◽  
Mrna Expression ◽  
Differential Expression ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Steroid Treatment ◽  
Ovarian Steroids ◽  
Protein Levels ◽  
Steroid Regulation

In this study, we investigated steroid regulation of the hyaluronan (HA) system in ovine endometrium including HA synthases (HAS), hyaluronidases, and HA receptor-CD44 using 30 adult Welsh Mountain ewes. Eight ewes were kept intact and synchronized to estrous (day 0). Intact ewes were killed on day 9 (luteal phase; LUT; n=5) and day 16 (follicular phase; FOL; n=3). The remaining ewes (n=22) were ovariectomized and then treated (i.m.) with vehicle (n=6) or progesterone (n=8) for 10 days, or estrogen and progesterone for 3 days followed by 7 days of progesterone alone (n=8). Estradiol and progesterone concentrations in plasma correlated with the stage of estrous or steroid treatment. Our results showed trends (P<0.1) and statistically significant effects (P<0.05, by t-test) indicating that LUT had lower HAS1 and HAS2 and higher HAS3 and CD44 mRNA expression compared with FOL. This was reflected in immunostaining of the corresponding HAS proteins. Similarly, in ovariectomized ewes, progesterone decreased HAS1 and HAS2 and increased HAS3 and CD44, whereas estradiol tended to increase HAS2 and decrease CD44. Sometimes, HAS mRNA expression did not follow the same trend observed in the intact animals or the protein expression. HA and its associated genes and receptors were regulated by the steroids. In conclusion, these results show that the level of HA production and the molecular weight of HA in the endometrium are regulated by ovarian steroids through differential expression of different HAS both at the gene and at the protein levels.

scholarly journals Structural Characterization and Antioxidant Activity of Polysaccharides from Athyrium multidentatum (Doll.) Ching in d-Galactose-Induced Aging Mice via PI3K/AKT Pathway

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3364 ◽  
Author(s):  
Liang Jing ◽  
Jing-Ru Jiang ◽  
Dong-Mei Liu ◽  
Ji-Wen Sheng ◽  
Wei-Fen Zhang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Weight ◽  
Protein Expression ◽  
Mrna Expression ◽  
Caspase 3 ◽  
Akt Pathway ◽  
Protective Mechanism ◽  
Related Factor ◽  
Bax Protein ◽  
Gene And Protein Expression

The purpose of this study was to characterize the polysaccharides from Athyrium multidentatum (Doll.) Ching (AMC) rhizome and explore the protective mechanism against d-galactose-induced oxidative stress in aging mice. Methods: A series of experiments, including molecular weight, monosaccharide composition, Fourier transform infrared (FT-IR) spectroscopy, and 1H nuclear magnetic resonance (1H NMR) spectroscopy were carried out to characterize AMC polysaccharides. The mechanism was investigated exploring d-galactose-induced aging mouse model. Quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) and western blotting assays were performed to assess the gene and protein expression in liver. Key findings: Our results showed that AMC polysaccharides were mainly composed of mannose (Man), rhamnose (Rha), glucuronic acid (Glc A), glucose (Glc), galactose (Gal), arabinose (Ara), and fucose (Fuc) in a molar ratio of 0.077:0.088:0.09:1:0.375:0.354:0.04 with a molecular weight of 33203 Da (Mw). AMC polysaccharides strikingly reversed d-galactose-induced changes in mice, including upregulated phosphatidylinositol 3-kinase (PI3K), Akt, nuclear factor-erythroid 2-related factor 2 (Nrf2), forkhead box O3a (FOXO3a), and hemeoxygenase-1 (HO-1) mRNA expression, raised Bcl-2/Bax ratio, downregulated caspase-3 mRNA expression, enhanced Akt, phosphorylation of Akt (p-Akt), Nrf2 and HO-1 protein expression, decreased caspase-3, and Bax protein expression. Conclusion: AMC polysaccharides attenuated d-galactose-induced oxidative stress and cell apoptosis by activating the PI3K/AKT pathway, which might in part contributed to their anti-aging activity.

scholarly journals Modulation of Neurological Deficits and Expression of Glutamate Receptors during Experimental Autoimmune Encephalomyelitis after Treatment with Selected Antagonists of Glutamate Receptors

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Grzegorz Sulkowski ◽  
Beata Dąbrowska-Bouta ◽  
Lidia Strużyńska
Keyword(s):  
Experimental Autoimmune Encephalomyelitis ◽  
Protein Expression ◽  
Mrna Expression ◽  
Glutamate Receptors ◽  
Neurological Deficits ◽  
Autoimmune Encephalomyelitis ◽  
Protein Levels ◽  
Group I ◽  
Group I Mglurs ◽  
Experimental Autoimmune

The aim of our investigation was to characterize the role of group I mGluRs and NMDA receptors in pathomechanisms of experimental autoimmune encephalomyelitis (EAE), the rodent model of MS. We tested the effects of LY 367385 (S-2-methyl-4-carboxyphenylglycine, a competitive antagonist of mGluR1), MPEP (2-methyl-6-(phenylethynyl)-pyridine, an antagonist of mGluR5), and the uncompetitive NMDA receptor antagonists amantadine and memantine on modulation of neurological deficits observed in rats with EAE. The neurological symptoms of EAE started at 10-11 days post-injection (d.p.i.) and peaked after 12-13 d.p.i. The protein levels of mGluRs and NMDA did not increase in early phases of EAE (4 d.p.i.), but starting from 8 d.p.i. to 25 d.p.i., we observed a significant elevation of mGluR1 and mGluR5 protein expression by about 20% and NMDA protein expression by about 10% over the control at 25 d.p.i. The changes in protein levels were accompanied by changes in mRNA expression of group I mGluRs and NMDARs. During the late disease phase (20–25 d.p.i.), the mRNA expression levels reached 300% of control values. In contrast, treatment with individual receptor antagonists resulted in a reduction of mRNA levels relative to untreated animals.

Parathyroid hormone stimulates endothelial expression of atherosclerotic parameters through protein kinase pathways

2007 ◽  
Vol 292 (4) ◽  
pp. F1215-F1218 ◽  
Author(s):  
Gloria Rashid ◽  
Jacques Bernheim ◽  
Janice Green ◽  
Sydney Benchetrit
Keyword(s):  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Protein Expression ◽  
Mrna Expression ◽  
Umbilical Vein ◽  
Protein Levels ◽  
Glycation End Products ◽  
Mrna And Protein Expression ◽  
Vascular Structures ◽  
The Impact

Parathyroid hormone (PTH), the major systemic calcium-regulating hormone, has been linked to uremic vascular changes. Considering the possible deleterious action of PTH on vascular structures, it seemed logical to evaluate the impact of PTH on the receptor of advanced glycation end products (RAGE) and interleukin 6 (IL-6) mRNA and protein expression, taking into account that such parameters might be involved in the pathogenesis of vascular calcification, atherosclerosis, and/or arteriolosclerosis. Human umbilical vein cord endothelial cells (HUVEC) were stimulated for 24 h with 10−12–10−10 mol/l PTH. The mRNA expression of RAGE and IL-6 was established by reverse transcriptase/PCR techniques. RAGE protein levels were determined by Western blot and IL-6 secretion was measured by ELISA. The pathways by which PTH may have an effect on HUVEC functions were evaluated. PTH (10−11–10−10mol/l) significantly increased RAGE mRNA and protein expression. PTH also significantly increased IL-6 mRNA expression without changes at protein levels. The addition of protein kinase (PKC or PKA) inhibitors or nitric oxide (NO) synthase inhibitors significantly reduced the RAGE and IL-6 mRNA expression and the RAGE protein expression. PTH stimulates the mRNA expressions of RAGE and IL-6 and the protein expression of RAGE. These stimulatory effects are probably through PKC and PKA pathways and are also NO dependent. Such data may explain the possible impact of PTH on the atherosclerotic and arteriosclerotic progression.

Relationship of ERCC1 genotype variant with mRNA expression and ERCC1 protein levels in advanced urothelial carcinoma (UC).

2013 ◽  
Vol 31 (6_suppl) ◽  
pp. 260-260
Author(s):  
Elizabeth A. Guancial ◽  
Lillian Werner ◽  
Joaquim Bellmunt ◽  
Nikitas Nikitas ◽  
Edward C. Stack ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Excision Repair ◽  
Predictive Biomarker ◽  
Mrna Levels ◽  
Nuclear Staining ◽  
Protein Levels ◽  
Tissue Arrays ◽  
Platinum Based Chemotherapy ◽  
The Relationship

260 Background: DNA repair factors may be predictive for response to chemotherapies that produce DNA damage. While low ERCC1 protein and mRNA levels have been reported as associated with improved outcomes in metastatic UC patients treated with platinum-based chemotherapy, the relationship between genotype, mRNA expression, and protein level is unknown. The ERCC1 germline 19007C>T single-nucleotide polymorphism (SNP) is functionally associated with reduced translation of ERCC1 mRNA. We investigated the relationship between ERCC1 germline SNP, ERCC1 tumor mRNA and protein expression, in a cohort of patients with advanced UC who received first-line, platinum-based chemotherapy. Methods: A cohort of clinically annotated, uniformly-treated advanced UC patients with FFPE primary tumor tissue available was identified through the Hellenic cooperative Oncology Group (HECOG) (N=93). Genomic DNA extraction, nested PCR, and restriction fragment length polymorphism techniques for the 19007C>T SNP were performed to identify C/C, C/T and T/T genotypes. ERCC1 mRNA expression was interrogated using Nanostring nCounter profiling. IHC analysis was performed on tissue arrays using an ERCC1 antibody. Percent of positive nuclear staining was categorized as quartiles using previously identified cut-points. Results: ERCC1 C/T genotype was identified in 30/61 samples (49%) and T/T in 14/61 samples (23%). In 54 patients with both SNP and mRNA data available, T/T genotype was associated with the highest level of mRNA expression, followed by the C/T genotype (p=0.04). Neither ERCC1 genotype (N=44) nor ERCC1 mRNA expression (N=54) was associated with ERCC1 protein expression as measured by IHC (p=0.52 and p=0.13, respectively). Conclusions: ERCC1 19007C>T is associated with increased ERCC1 mRNA expression. However, neither genotype nor mRNA are surrogates for ERCC1 protein detected by IHC in advanced UC tumors. This suggests that while genotype influences mRNA expression of ERCC1, the use of the nucleotide excision repair pathway as a predictive biomarker of platinum-sensitivity may be more complex than previously appreciated and require the integrative use of proteomics, genomics and epigenomics.

Changes in the Dopaminergic Control of Prolactin Secretion and in Ovarian Steroids in Migraine

Cephalalgia ◽  
1986 ◽  
Vol 6 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Giovanni Murialdo ◽  
Emilia Martignoni ◽  
Andrea De Maria ◽  
Maria Luisa Bonura ◽  
Grazia Sances ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Healthy Subjects ◽  
Inhibitory Effect ◽  
Prolactin Secretion ◽  
Follicular Phase ◽  
Ovarian Steroids ◽  
Da Receptors ◽  
Dopaminergic Supersensitivity ◽  
Responses To Dopamine ◽  
Dopaminergic Control

Prolactin (PRL) responses to dopamine (DA) blockers and to direct and indirect DA agonists have been studied in 23 healthy women, 17 women with catamenial migraine and 17 with non-catamenial migraine in both their follicular and luteal phases. PRL responses to the DA blockers were greater in the follicular phase of both migraine groups than in controls. The inhibitory effect of nomifensine on PRL secretion was dampened in the follicular phase of both migraine groups. These findings demonstrate an increased PRL reserve in migraine and suggest the existence of a dopaminergic supersensitivity of the lactotrophic postsynaptic DA receptors. The impaired inhibitory effect of nomifensine on PRL secretion hints at a decrease of the presynaptic DA content in tuberoinfundibular DA neurons. In migrainous women 17-β-oestradiol levels are higher in both ovarian phases, whereas progesterone concentrations and the progesterone to oestradiol ratio are lower than in healthy subjects in the luteal phase. These data suggest the existence of a change in the oestrogen-dependent modulation of pituitary DA receptors.

scholarly journals The effect of elevated progesterone and pregnancy status on mRNA expression and localisation of progesterone and oestrogen receptors in the bovine uterus

Reproduction ◽  
2010 ◽  
Vol 140 (1) ◽  
pp. 143-153 ◽  
Author(s):  
L A Okumu ◽  
N Forde ◽  
A G Fahey ◽  
E Fitzpatrick ◽  
J F Roche ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Treatment Effect ◽  
Luteal Phase ◽  
Luminal Epithelium ◽  
Oestrogen Receptors ◽  
Protein Expressions ◽  
Pregnancy Status ◽  
Effect Of Treatment ◽  
Intravaginal Device

To investigate the effects of pregnancy or post-ovulatory progesterone (P4) supplementation on the expression of oestrogen and P4 receptors (ESRs and PGRs) in the bovine uterus, heifers (n=263) were randomly assigned to the following treatments: i) cyclic, normal P4; ii) cyclic, high P4; iii) pregnant, normal P4; and iv) pregnant, high P4 on days 5, 7, 13 and 16 of pregnancy/oestrous cycle. Elevated P4 was achieved through P4-releasing intravaginal device insertion on day 3 after oestrus, resulting in increased concentrations from day 3.5 to 8 (P<0.05) in the high groups than in the normal groups. Irrespective of treatment, PGR and ESR1 mRNA expressions were highest on days 5 and 7 and decreased on day 13 (P<0.05), while ESR2 mRNA expression increased on day 7 (P<0.05) and similar levels were maintained within the normal P4 groups subsequently. Expression in the high P4 groups decreased on day 13 (P<0.05). PGR-AB and PGR-B protein expressions were high in the luminal and superficial glands on days 5 and 7, but by day 13, expression had declined to very low or undetectable levels and high P4 concentration tended to decrease or decreased significantly (P<0.05) the expression in these regions on days 5 and 7. ESR1 protein expression was high, with no treatment effect. ESR2 protein was also highly expressed, with no clear effect of treatment. In conclusion, early post-ovulatory P4 supplementation advances the disappearance of PGR protein from the luminal epithelium on days 5 and 7, and decreases ESR2 mRNA expression during the mid-luteal phase, but has no effect on PGR or ESR1 mRNA expression.

Luteal phase ovarian stimulation versus follicular phase ovarian stimulation results in different human cumulus cells gene expression: a pilot study

2020 ◽  
Author(s):  
Li-Te Lin ◽  
Ju-Yueh Li ◽  
Kuan-Hao Tsui ◽  
Chia-Jung Li ◽  
Peng-Hui Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Ovarian Stimulation ◽  
Luteal Phase ◽  
Cumulus Cells ◽  
Follicular Phase ◽  
Basic Characteristics ◽  
The Impact ◽  
Luteal Phase Ovarian Stimulation

Abstract OBJECTIVE: Physiologic elevated levels of progesterone in luteal phase can impede early-onset LH surge. However, the impact of high levels of progesterone on the oocyte or cumulus cells (CCs) remains indistinct. Therefore, the aim of study was to investigate the CCs gene expression between luteal phase ovarian stimulation (LPOS) and follicular phase ovarian stimulation (FPOS) in poor ovarian responders (PORs) undergoing in vitro fertilization (IVF) cycles. MATERIALS AND METHODS: This was a prospective non-randomized trial (ClinicalTrials.gov Identifier: NCT03238833). A total of 36 PORs who conformed Bologna criteria and underwent IVF cycles were enrolled. 15 PORs were allocated to the LPOS group and 21 PORs were allocated to the FPOS group. Basic characteristics, cycle characteristics and pregnancy outcomes were compared between the two groups. Moreover, CCs genes regarding inflammation (CXCL1, CXCL3, TNF, PTGES), oxidative-phosphorylation (NDUFB7, NDUFA4L2, SLC25A27), apoptosis (DAPK3, BCL6B) and metabolism (PCK1, LDHC) were analyzed using real-time quantitative PCR between the two groups. RESULTS: Basic characteristics and IVF outcomes were similar between the two groups except significantly high progesterone level in the LPOS group. The mRNA expression of CXCL1 and PTGES were significantly lower in the LPOS group than in the FPOS group ( p < 0.05). The LPOS group had significantly lower mRNA expression of NDUFB7 and NDUFA4L2 than the FPOS group ( p < 0.05). DAPK3 and BCL6B mRNA expression were significantly higher in the LPOS group compared to FPOS group ( p < 0.05). Increased expression of PCK1 and decreased expression of LDHC were observed in the LPOS group compared to the FPOS group. ( p < 0.05). CONCLUSIONS: Compared to the FPOS, the LPOS seemed to reduce favorable inflammation and mitochondrial function, and induce apoptosis and abnormal glucose metabolism in CCs.

Bromodomain Inhibition By OTX015 Regulates c-MYC and HEXIM1 in a Panel of Human Acute Leukemia Cell Lines

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5957-5957
Author(s):  
Marie-Magdelaine Coudé ◽  
Thorsten Braun ◽  
Jeannig Berrou ◽  
Mélanie Dupont ◽  
Raphael Itzykson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Mrna Expression ◽  
Rna Polymerase Ii ◽  
Cell Lines ◽  
Leukemia Cell ◽  
K562 Cells ◽  
Antileukemic Activity ◽  
Protein Levels ◽  
Gene And Protein Expression

Abstract Background: The bromodomain-containing protein 4 (BRD4) activates the transcription elongation factor b (P-TEFb) which regulates RNA polymerase II. Conversely, hexamethylene bisacetamide (HMBA) inducible protein 1 (HEXIM1) inactivates P-TEFb. BRD4/HEXIM1 interplay influences cell cycle progression and tumorigenesis. It has been widely demonstrated that BRD4 knockdown or inhibition by JQ1 is associated with c-MYC downregulation and antileukemic activity. We recently reported that the small molecule BRD2/3/4 inhibitor OTX015 (Oncoethix, Lausanne, Switzerland), currently in clinical development, mimics the effects of JQ1 (Braun et al, ASH 2013). We evaluated the effect of OTX015 on c-MYC, BRD2/3/4, and HEXIM1 in human in vitro leukemic models. Methods: c-MYC, BRD2/3/4 and HEXIM1 expression was assessed in six acute myeloid leukemia (AML; K562, HL-60, NB4, NOMO-1, KG1, OCI-AML3) and two acute lymphoid leukemia (ALL; JURKAT and RS4-11) cell lines after exposure to 500 nM OTX015. Quantitative RT-PCR and Western blotting were performed at different time points (24-72h). A heatmap was computed with R-software. Results: c-MYC RNA levels were ubiquitously downregulated in all AML and ALL cell lines after 24h exposure to OTX015 (Figure 1). c-MYC protein levels decreased to a variable extent at 24-72h in all cell lines evaluated other than KG1. BRD2, BRD3 and BRD4 mRNA expression was significantly decreased in K562 cells (known to be OTX015-resistant) after 48h exposure to OTX015 but was increased in HL60 and NOMO-1 cells, while minimal to no increases were observed in other cell lines. OTX015 induced a decrease in BRD2 protein expression in most cell lines, but not in K562 cells. In contrast, decreased BRD4 protein expression was only seen in the OCI-AML3, NB4 and K562 cell lines. BRD3 protein levels were not modified after OTX015 exposure in all cell lines evaluated other than KG1. HEXIM1 mRNA expression increased after 24h exposure to 500 nM OTX015 in all cell lines except OTX015-resistant K562 cells in which the increase was considered insignificant (less than two-fold). Increases in HEXIM1 protein levels were observed in OCI-AML3, JURKAT and RS4-11 cell lines at 24-72h but not in K562 cells. Conclusion: Taken together, these results show that BRD inhibition by OTX015 modulates HEXIM1 gene and protein expression, in addition to c-MYC decrease and BRD variations. HEXIM1 upregulation seems to be restricted to OTX015-sensitive cell lines and was not significantly affected in OTX015-resistant K562 cells. Further studies are needed to clarify the role of HEXIM1 in antileukemic activity of BRD inhibitors. Figure 1: Heatmap of gene expression after exposure to 500 nM OTX015 for 24 or 48h in AML and ALL cell lines. Repression in blue. Overexpression in red. Figure 1:. Heatmap of gene expression after exposure to 500 nM OTX015 for 24 or 48h in AML and ALL cell lines. Repression in blue. Overexpression in red. Disclosures Riveiro: OTD: Employment. Herait:OncoEthix: Employment. Dombret:OncoEthix: Research Funding.

scholarly journals Innate Immunity Components and Cytokines in Gastric Mucosa in Children withHelicobacter pyloriInfection

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Jacek Michalkiewicz ◽  
Anna Helmin-Basa ◽  
Renata Grzywa ◽  
Mieczyslawa Czerwionka-Szaflarska ◽  
Anna Szaflarska-Poplawska ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Gastric Mucosa ◽  
Protein Expression ◽  
Mrna Expression ◽  
Lymphocytic Infiltration ◽  
Natural Immunity ◽  
Gene Expressions ◽  
Protein Levels ◽  
Anti Inflammatory ◽  
H Pylori

Purpose.To investigate the expression of innate immunity components and cytokines in the gastric mucosa amongH. pyloriinfected and uninfected children.Materials and Methods.Biopsies of the antral gastric mucosa from children with dyspeptic symptoms were evaluated. Gene expressions of innate immunity receptors and cytokines were measured by quantitative real-time PCR. The protein expression of selected molecules was tested by immunohistochemistry.Results. H. pyloriinfection did not lead to a significant upregulation ofMyD88, TLR2, TLR4, CD14, TREM1,andTREM2mRNA expression but instead resulted in high mRNA expression ofIL-6, IL-10, IFN-γ, TNF-α,andCD163. H. pylori cagA(+) infection was associated with higherIL-6andIL-10mRNA expression, as compared tocagA(−) strains.H. pyloriinfected children showed increased IFN-γand TNF-αprotein levels. IFN-γmRNA expression correlated with bothH. pyloridensity of colonization and lymphocytic infiltration in the gastric mucosa, whereas TNF-αprotein expression correlated with bacterial density.Conclusion. H. pyloriinfection in children was characterized by (a) Th1 expression profile, (b) lack of mRNA overexpression of natural immunity receptors, and (c) strong anti-inflammatory activities in the gastric mucosa, possibly resulting from increased activity of anti-inflammatory M2 macrophages. This may explain the mildly inflammatory gastric inflammation often observed amongH. pyloriinfected children.

scholarly journals Peripheral concentrations of inhibin A, ovarian steroids, and gonadotropins associated with follicular development throughout the estrous cycle of the sow

Reproduction ◽  
2010 ◽  
Vol 139 (1) ◽  
pp. 153-161 ◽  
Author(s):  
Michiko Noguchi ◽  
Koji Yoshioka ◽  
Seigo Itoh ◽  
Chie Suzuki ◽  
Sachiko Arai ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Luteal Phase ◽  
Inverse Relationship ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Follicular Phase ◽  
Follicular Growth ◽  
Inhibin A ◽  
Ovarian Steroids ◽  
Feedback Regulator

We investigated changes in peripheral concentrations of inhibin A, total inhibin, steroids, and gonadotropins throughout the intact estrous cycle of the sow in relation to ovarian changes determined by daily transrectal ultrasonography. All visible follicles of 3 mm or more in diameter were classified as small (≥3 and <6 mm) or large (≥6 mm). Follicular recruitment was identified in two periods of the cycle: one from the late luteal to the follicular phase, characterized by an increase in the number of small follicles followed by the appearance of large follicles; and another during the early luteal phase, consisting only of increased numbers of small follicles. Plasma concentrations of inhibin A increased (P<0.05), coinciding with the two periods of follicle emergence. Estradiol (E2) levels increased (P<0.05) during the follicular phase, but not during the early luteal phase. An inverse relationship (P<0.01) between the patterns of inhibin and FSH concentrations was noted around the two periods of follicle emergence, but there was no relationship (P≥0.1) between the patterns of plasma E2and FSH during the early luteal phase. In conclusion, measurement of plasma inhibin A levels combined with ultrasonographic examination of the ovaries revealed two periods of synchronous follicular growth during the sow's estrous cycle. The results strongly suggest that inhibin A functions as a negative feedback regulator of FSH secretion throughout the estrous cycle, whereas E2appears to influence FSH secretion only during the follicular phase.

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